Adding an Air Condition Vent to a Room

I wanted to know the approximate cost to add an air condition vent to a bedroom that only has one a/c vent at this time. It gets too hot in the summer, compared to the rest of the house. It's a one-story house and the attic is fairly easily accessible where the vent needs to go.

Sean ~ Arlington, Texas

Adding an additional vent is not necessarily going to fix the problem. When HVAC systems are installed they are sized specifically for the space and ducts are sized for each individual room. By adding an additional vent to one room you may reduce the flow to another room, thus making another room warmer or colder. There are some options here that you may want to try first, before you get a HVAC specialist involved. Are there skylights in the room? If there are, try covering them on the outside to reduce the solar gain during the day. Does the room in question have windows that are in direct sunlight during the day? If so, try hanging a sunshade on the outside of the window. Check and see in you have sufficient ceiling insulation over that room. Check the air filter on your HVAC system and make sure it is clean. If one room is dramatically cooler than the rest, try closing the vent register a little bit and see if it helps increase air flow to other rooms. If none of these options help, call an HVAC specialist. They can make sure that your system is working properly, make sure that is full of refrigerant, check the ductwork for leaks and clogs, and determine if the installation of an additional vent will work in your situation. The addition of an extra vent will only cost a couple hundred dollars, but make sure that your system will support the addition of this extra vent first.